http://numbersapi.com/37
should return a trivia fact about the number 37, or try another number. Makes a nice site for testing a web request script.
Another site useful for testing. I believe at least half the sites used in our web-related regression testing are sites you have found over the years.
I tried n=104
and got - 104 is the atomic number of rutherfordium. No wonder I hated chemistry, I thought it was rubadoobiam.
I'm fond of "Uhm"... the element of surprise. Also, unobtanium is supposed to be fun stuff to play with, but nobody seems to be able to supply it.